578 nm clock laser system for ytterbium quantum gas experiments

Abstract

Ultra-narrow clock transition of ytterbium atoms has enabled not only quantum metrology but also quantum simulation of various quantum phenomena. One of such examples is a new possibility of realizing dissipative open quantum systems with minimal heating by optical pumping through the clock transition. Nevertheless, the access to the clock transition and relevant optical pumping often requires a complex laser system. Here we delineate a simple design and characterization of a home-made clock laser system that is capable of driving ytterbium clock transition at 578 nm. A fundamental laser at 1156 nm based on a quantum dot gain chip in a long external cavity configuration seeds the standard bow-tie cavity and generates up to 45 mW power of frequency-doubled yellow light at 578 nm. We have stabilized the laser frequency to a high-finesse ULE (ultra-low expansion) cavity via electronic feedback to the current. We examine the atomic spectroscopy at the clock transition in fermionic $^{173}$Yb atoms, which would allow us to implement controlled dissipation with minimal heating. With the clock laser system built in this work, we envision exploring non-Hermitian physics in various platforms including spin-orbit-coupled fermions and topological bands.